Isomeric characterization via ion neutralization and dissociation. Experimental variables

Major deficiencies of mass spectrometry for characterizing isomeric molecules, and of collisionally activated dissociation for characterizing isomeric ions, can be alleviated by complementary information from new techniques of neutraiization-reionization (NR) mass spectrometry. Mass data can be obtained from most fragments of the original species, irrespective of their ability to retain the charge; dissociation of fast neutrals prepared from isomeric ions can involve novel reaction pathways and can minimize competing isomerization reactions; isomeric neutrals undergoing similar dissociations can be differentiated by forming them with different internal energies; reionization of the neutral products to negative as well as positive ions can provide increased selectivity; and structural information on the resulting ions can be derived using MS/MS/MS, Dissociation by novel non-isomerization pathways can also be effected by a second addition (or subtraction) of an electron to produce an unstable ion of opposite charge. Special techniques can yield neutralized products in favorable dissociative states by collisional activation, by using neutralization targets of selected ionization energy, or through Franck-Condon factors. Optimum excitation of the neutral is important, as this should be high enough to minimize rearrangement, to maximize the differences in the dissociation pathways of isomers, and to minimize the further dissociation of the characteristic primary products of the neutral. NR experiments can, thus, also provide information on the energy surfaces for unimolecular dissociations of neutrals that are difficult to study by conventional techniques. Dissociations of the neutrals can be differentiated from those occurring after reionization by separate collisional activation of the neutrals, by changing the ionization energy of the neutralization agent, or by reionization to ions of opposite charge.     

Rapid Identification of Specific Proteins in Eluants from Chromatographic Separations

Abstract

The identity of proteins from chromatographic separations can be rapidly determined by immunoelectroosmophoresis. Column eluants can be serologically assayed by several specific antisera in 30 minutes. The assay is only limited by the number of specific anti-sera that can be prepared or commercially obtained.     

应用相图边界理论勾画多元恒温截面相图

根据相图的边界理论,可以确定恒温截面图中紧邻相区及其边界关系,进而可以根据有限的实验数据,比较直接地勾画出整个恒温截面图。本文以5元相图和8元相图为例加以说明。     

Light activated patterning of dye-labeled molecules on surfaces

This Communication describes a novel method for patterning proteins, ligands, or other organic/inorganic species onto solid substrates. The process works by linking the moiety of interest to a fluorophore that can be subsequently photobleached and bound to the interface. The technique can be performed in aqueous solution and allows several species to be addressed onto the surface simultaneously by using different frequencies of light. Because the method can be used with fluorophores excited by visible light, shorter and more damaging wavelengths can be avoided.     

Neue verfahren zur jodometrischen mikrobestimmung von jodid- bzw. Bromidion

The methods described above are based on the fact, that iodide can be determined as iodate on iodometric way after oxidation with freshly prepared chlorine water and after removal of excess of free chlorine by means of potassium cyanide. However oxidation may be carried out by adding of hypobromite the excess of which can be removed by adding of phenol water.Bromide can be transformed to BrCl by means of an excess of chlorine water. BrCl reacts with potassium cyanide under formation of cyanogen bromide and chloride. The excess of free chlorine would be removed as cyanogen chlorine and chloride. The cyanogen bromide formed can be measured on the usual iodometric way.     

Structure of Porous Adsorbents

Porous solids are gaining in importance as adsorbents and catalysts both for scientific investigations and for industrial applications. Adsorbents having predetermined pore structure can be prepared by specific synthesis. This pore structure can be described in detail and comprehensively by specific parameters, which can be determined by gas adsorption measurements and by other means. Information concerning the bonding state and the concentration of the functional groups on the surface is obtainable by the use of chemical and physical methods of investigation. Other functional groups can be attached to the surface by chemical reactions. It is possible in this way to prepare selective adsorbents.     

化学改性麦壳对孔雀绿的吸附作用

通过不同的化学方法对农业副产物麦壳进行改性,以制得廉价的生物吸附剂,并分别研究了它们对孔雀绿的吸附性能。结果表明,天然麦壳对孔雀绿有一定的吸附量,经化学修饰后对孔雀绿的吸附量有不同程度的提高,其中,经硝酸酸化后的麦壳对孔雀绿的吸附效果最好。通过研究硝酸改性麦壳吸附孔雀绿条件的影响发现,吸附40min达到平衡;随初始浓度增加,吸附量增大;溶液在中性或碱性范围内,吸附量较高;吸附符合Langmuir和Freundlich等温模型,吸附动力学过程可以用准二级动力学方程来较好地拟合。因此,硝酸改性麦壳可以用于有效去除水体中的孔雀绿。     

稀土氧化物对中高碳钢堆焊金属中夹杂物变质作用的热力学分析

采用热力学方法,研究了稀土氧化物对中高碳钢堆焊金属中夹杂物的变质作用。夹杂物生成的热力学分析表明,在堆焊熔池中,稀土氧化物可以被碳还原成稀土元素,稀土元素可以与氧、硫生成稀土氧化物、稀土硫化物和稀土硫氧化物,从而达到脱氧、脱硫、净化堆焊熔池的作用;稀土氧化物还可以直接与硫作用,生成稀土硫氧化物,起到脱硫的效果。     

A circular dichroism detection of stereostructural change due to amine protonation

Aromatic amine conformation can be controlled by protonation and this process can be followed by circular dichroism measurements.     

Thermometric and conductometric observation of copper(ii)-catalyzed reactions in the catalytic-kinetic difference method : Determination of microgram amounts of copper(ii)

The course of reactions in the catalytic-kinetic difference method, previously described, can also be followed by conductometry and thermometry. The copper-catalyzed decomposition of hydrogen peroxide can be followed by thermometry, and the copper-catalyzed oxidation of thiosulfate with hydrogen peroxide by conductometry. Both reactions can be used for the determination of microgram amounts of copper(II).     

Enhancing the information content of vibrational spectra through sample perturbation

Infrared and Raman band frequencies, intensities and line shapes are often sensitive to the local molecular environment determined by molecular conformation, surrounding matrix, temperature, pressure, etc. The variety of local environments experienced by a condensed-phase molecule can lead to vibrational spectra with broad bands containing many overlapped spectral features. The spectral resolution of these overlapped features can be enhanced by making perturbations to the sample environment. Examples of perturbations which can be applied to the sample to enhance the information content of infrared spectra are changes in temperature, concentration and mechanical strain. In each instance, the spectra obtained as a function of the perturbation can be cross-correlated to produce a two-dimensional correlation map defined by two independent wavenumber axes. in this representation, infrared bands which respond to the perturbation in a similar or different manner can be clearly identified. This information can be used to help resolve overlapped bands and make unambiguous band assignments.     

Polymers Containing Lactone Groups

Polymers containing intact lactone groups are a new class of macromolecules with reactive groups, which are relatively easy to obtain by polymerization, polycondensation and polyaddition, as well as by reactions on existing macromolecules. Polymers with β-lactone Groups in particular can enter into numerous addition reactions, which can be used, for example, to obtain macromolecules containing hydroxy acid or amino acid groupings. The reactions proceed under mild conditions, and can even be carried out in aqueous media, frequently giving water-soluble polymers. The polymers can be cross-linked at low temperatures, even from the aqueous phase, by the addition of bifunctional or oligofunctional reagents. Polymers containing β-lactone groups can also be used as a basis for graft co-polymers; polyester or polyether branches can be grafted on, depending on whether monomeric lactones or monomeric epoxides are used.     

Failure Prediction Modeling of Lithium Ion Battery toward Distributed Parameter Estimation

Lithium ion battery has typical character of distributed parameter system, and can be described precisely by partial differential equations and multi-physics theory because lithium ion battery is a complicated electrochemical energy storage system. A novel failure prediction modeling method of lithium ion battery based on distributed parameter estimation and single particle model is proposed in this work. Lithium ion concentration in the anode of lithium ion battery is an unmeasurable distributed variable. Failure prediction system can estimate lithium ion concentration online, track the failure residual which is the difference between the estimated value and the ideal value. The precaution signal will be triggered when the failure residual is beyond the predefined failure precaution threshold, and the failure countdown prediction module will be activated. The remaining time of the severe failure threshold can be estimated by the failure countdown prediction module according to the changing rate of the failure residual. A simulation example verifies that lithium ion concentration in the anode of lithium ion battery can be estimated exactly and effectively by the failure prediction model. The precaution signal can be triggered reliably, and the remaining time of the severe failure can be forecasted accurately by the failure countdown prediction module.     

简便荧光法测定Fenton反应产生的羟自由基

简便荧光法测定Fenton反应产生的羟自由基;芬顿反应;羟自由基;亮绿SF;荧光光度法     

Derivative spectrophotometric determination of mercury(II) with pan in the aqueous phase

The Hg-PAN complex can be made soluble in water by addition of surfactant, and this can be made the basis of a spectrophotometric determination of Hg at ppm level. The selectivity and sensitivity can be improved by use of derivative spectrometry. The method has been applied to mercury-containing pesticides.     

Separation of different forms of transferrin by isoelectric focusing to detect effects on the liver caused by xenobiotics

Several genetic variants and also isoforms of transferrin differing in carbohydrate structure can be separated by polyacrylamide or agarose gel isoelectric focusing. Numerous blood plasma or serum samples can be analyzed in parallel in each gel. Studies of the heterogeneity of transferrin have already revealed many results of importance to different fields of human medicine. Gene typing can give important and useful information for paternity determination and in forensic medicine. The gene type C 2 seems to have increased frequency in certain malfunctions. Futhermore, functional abnormalities of liver cells can be revealed by determination of the concentrations of transferrin isoforms differing mainly in their carbohydrate parts. The isoforms can be quantified with zone immunoelectrophoresis assay. Thus valuable information can be obtained about important modulated regulations of cell and membrane functions, even when these are disturbed by disease and xenobiotics. The information may be useful e.g. in the detection of individuals suffering from toxic effects, to identify toxic agents and exposure conditions. Studies of house painters revealed that exposure to different types of paints had an effect on transferrin. Determination of the concentration of the isotransferrin with pI 5.7 in blood samples from alcoholics can be used as a marker for the detection of liver dysfunction and for the monitoring of therapy treatments. In addition, by analyzing the isotransferrins a rare genetic abnormality can be detected.     

Alkyl Chain Introduction: In Situ Solar‐Renewable Colorful Organic Mechanoluminescence Materials

Mechanoluminescence (ML) materials are environmentally friendly and emit light by utilizing mechanical energy. This has been utilized in light sources, displays, bioimaging, and advanced sensors. Organic ML materials are strongly limited to application by in situ unrepeatable ML. Now, in situ solar‐renewable organic ML materials can be formed by introducing a soft alkyl chain into an ML unit. For the first time, the ML from these polycrystalline thin films can be iteratively produced by simply recrystallizing the fractured crystal in situ after a contactless exposure to sunlight within a short time (≤60 s). Additionally, their ML color and lifetime can be also easily tuned by doping with organic luminescent dyes. Therefore, large‐area sandwich‐type organic ML devices can be fabricated, which can be repeatedly used in a colorful piezo‐display, visual handwriting monitor, and sensitive optical sensor, showing a lowest pressure threshold for ML of about 5 kPa.     

Construction and evaluation of a novel end-column amperometric detection system for electrophoresis microchips

A set of integrated end-column amperometric detection system has been developed,onto which an electrophoresis microchip can be conveniently integrated.Finely machined by a piece of transparent organic glass,the system consists of an electrophoresis microchip platform and an amperometric detection reservoir,in which the microchip can be fixed onto the platform by microchip grooves and with stainless steel fixture.Each detection electrode can be directly fixed in the amperometric detection reservoir by screws...     

催化裂化催化剂中微量金属元素的测定

原料油中的微量金属元素会污染催化裂化催化剂而使其中毒,对于使用中的再生、平衡催化裂化催化剂进行微量金属元素含量分析,可以有效地指导炼油厂的生产．通过对检出限、重复性以及准确性的考察．表明等离子发射光谱法测定催化剂中微量金属元素含量检出限低、重复性好、准确度高、且具有多元素同时测定以及线性范围宽的特性,是催化裂化催化剂中金属元素含量快速测定的最有效方法之一．     

漂白过程的电化学研究 Ⅲ.利用旋转圆盘电极模拟照相漂白过程

将银旋转圆盘电极在给定时间内浸在漂白液中进行氧化。在氧化过程中,来自漂白液中的卤化物在银电极表面与氧化生成的银离子形成卤化银。氧化反应生成的卤化银量可以用电化学还原方法进行定量测定。利用这种简单的方法可以研究漂白动力学,研究漂白液的组份、浓度和pH对漂白速度的影响。通过记录在银电极上氧化还原对的电流。电位曲线可以定量描述漂白过程。